JP2010235354A - Sheet glass forming method - Google Patents

Abstract

In roll-out molding of molten glass, when the plate width is widened, some visually observable streaks are likely to occur in the traveling direction of the glass ribbon, and there is a need to solve this.
A method of forming molten glass flowing down from a molten glass supply apparatus into sheet glass by passing between paired rolls, wherein the roll is made of a material or structure that can contain a liquid therein. The glass ribbon is formed through a liquid vapor film between the rolls while rotating the uppermost roll placed in a pair so that the roll is placed under the molten glass supply device. Rolled out of molten glass, characterized in that the glass ribbon is fed in a direction and heated at the end of the fed glass ribbon, and then rolled and formed with one or more pairs of rolls installed vertically below the uppermost roll. Molding method.
[Selection] Figure 1

Description

  The present invention relates to a roll-out molding method for molten glass by a roll-out method.

  Various methods for forming molten glass into a plate shape are known. Particularly popular are the tin float method, the fusion method and the rollout method.

  The tin float method is currently most widely used as a mass production method for sheet glass, and is a method in which glass is floated on molten tin and stretch-formed. However, the metal tin that is solid at room temperature must be kept in a molten state at all times, so the energy required to keep the kiln warm is enormous. In addition, tin ions diffuse from the tin / molten glass interface into the glass, which may adversely affect the glass quality.

  The fusion method is a method in which molten glass flows down along both side surfaces of a refractory molded body, and the glass is joined at the lower part of the molded body. In this method, since the surface is kept in a non-contact state, a high-quality plate glass can be obtained. However, if devitrification occurs on the contact surface between the refractory and the molten glass, defects will occur continuously, so the refractory must be replaced, and the refractory increases as the glass width increases. The manufacturing cost of the system is enormous. Moreover, since it is necessary to consider the compatibility of a refractory and a glass composition in order not to cause devitrification, the glass composition which can be used is limited.

  The roll-out method is generally a method in which a molten glass is sandwiched between metal rolls and molded, and has an advantage that glass molding can be performed with a simple apparatus configuration at a lower cost than the tin float method and the fusion method. However, since the molten glass is rapidly cooled by contact with the metal roll, it is inevitable that contact marks, wrinkles, and undulations remain on the formed glass, and a polishing process is required to obtain a high-quality sheet glass product. It is essential.

  In view of these circumstances, a method has been proposed in which a roll base material that generates steam is used to impart conveying force to glass and roll-out molding to obtain high-quality glass that does not leave roll marks (Patent Documents). 1 and 2).

JP 2001-180949 A JP 2002-47019 A

  In the forming method described in Patent Documents 1 and 2 described above, a method of supplying molten glass between a pair of rotating rolls and adjusting the thickness by forming tension between the plurality of rolls in the glass traveling direction. Although it was taken, there was no description about the method of shape | molding a glass ribbon wide. As a method of widening the width of the glass, a method of narrowing between the rolls of a pair of rolls is considered to be effective, but if this method is used, several glass ribbons can be visually observed in the direction of travel. There is a need to solve this problem.

  As a result of earnestly studying the above problems, the present applicant has found that when the molten glass spreads in the width direction on the roll, the point where the temperature is lowered and difficult to spread in the width direction becomes the aforementioned streaks. Obtained. From the obtained knowledge, when the molten glass is formed into a glass ribbon, it is formed into a width that does not cause streaks, the end of the formed glass ribbon is heated, and further rolled and formed with a roll. Has come to provide a way to solve.

  That is, the present invention is a method of forming molten glass flowing down from a molten glass supply apparatus into a sheet glass by passing between paired rolls, and the base is made of a material or structure that can contain a liquid inside. While forming the glass ribbon through the liquid vapor film between the rolls while rotating the uppermost roll, which is made of a material and installed so that the roll is paired under the molten glass supply device, at the same time, the formed glass ribbon A molten glass roll characterized by being fed downward and heating the end of the fed glass ribbon, followed by rolling with one or more pairs of rolls installed vertically below the uppermost roll. This is an out-molding method.

  Further, in the roll-out molding method for molten glass according to the present invention, the distance between the rolls of the roll pair installed in the vertically downward direction of the uppermost roll to which the molten glass is supplied is smaller than the distance between the rolls of the upper roll. 50% or more.

  In the molten glass roll-out molding method of the present invention, the liquid that forms the vapor film is water.

  By this invention, it became possible to extend in the width direction without impairing the quality of the glass ribbon.

  The present invention relates to a method of forming molten glass flowing down from a molten glass supply apparatus into sheet glass by passing between paired rolls, and the base material is made of a material or structure that can contain a liquid inside. The glass ribbon is formed through a liquid vapor film between the rolls while rotating the uppermost roll installed so that the roll is placed in a pair under the molten glass supply device. Rolled out of molten glass, characterized in that the glass ribbon is fed in a direction and heated at the end of the fed glass ribbon, and then roll-formed with one or more pairs of rolls installed vertically below the uppermost roll. This is a molding method.

  FIG. 1 is a side view schematically showing an example of a roll-out molding apparatus for a sheet glass product for carrying out the present invention, and FIG. 2 is a front view. The forming apparatus includes a pair of uppermost roll 3 and roll 7 having a base material capable of containing water on the surface, a device 4 for supplying liquid thereto, and a device 5 for heating glass ribbon 6.

  Above the roll-out molding apparatus, there is a molten glass supply apparatus 1, which is an apparatus that can supply molten glass 2 that has been melted from the raw material over a sufficient time at a desired temperature. The molten glass 2 is supplied onto the paired uppermost roll 3 and spreads in the width direction on the roll 3. The molten glass 2 spread to a desired width on the roll 3 passes between the rolls 3 while being formed into a plate shape by the roll 3.

  At this time, the distance from the uppermost roll 3 to the molten glass supply device 1, the rotation speed of the roll, the temperature of the molten glass supplied onto the roll, and the flow rate of the supplied molten glass are appropriately set according to the desired glass ribbon. It is desirable that In particular, since the width of the glass ribbon formed by the uppermost roll 3 is affected by the molten glass temperature and the flow rate of the molten glass, it is desirable that the distance between the rolls can be set freely. Furthermore, if the gap between the rolls is too narrow, the molten glass may not flow out, or there may be frequent streaks on the glass ribbon to be molded, and on the other hand, if the gap between the rolls is too wide, roll molding may not be possible. It is desirable that the distance between the rolls is set appropriately.

  As for the roll base material that can contain the liquid on the roll surface, examples of the material include porous inorganic materials, metal materials, carbon materials, paper, and fibers. The properties required for these materials are heat resistance against radiant heat from the molten glass 2 and the heating device 5 received through the vapor film, water content capable of holding a sufficient amount of liquid on the rotating roll, For example, water absorption speed and surface flatness.

  The liquid supply device 4 to the roll substrate is a device that can supply a sufficient amount of liquid to the rotating roll. In addition to the water tank type as shown in FIGS. It is done. Further, one more roll containing sufficiently liquid may be installed, and the liquid may be supplied to the base material of the uppermost roll 3 and the roll 7 by contacting somewhere on the uppermost roll 3 and the roll 7. .

  Further, the liquid supplied to the roll base material is preferably a gas that forms a vapor film on the roll surface, not a gas near room temperature, but a gas at least above the glass transition point. The liquid is vaporized by the high heat of the molten glass 2 and the glass ribbon 6, and forms a vapor film between the glass and the roll. The liquid should have low toxicity, be non-flammable at the temperature used, and should not react chemically enough to cause the vaporized vapor to adversely affect the glass and roll, to increase water and hydrophilicity. An aqueous solution to which an alcohol is added, an aqueous solution to which a surfactant is added, or the like can be given.

  After the molten glass 2 is formed into the glass ribbon 6, both ends of the glass ribbon 6 are heated by the heating device 5 and further spread in the width direction by passing through the roll 7.

  At this time, the number of heating devices 5 and rolls 7 does not need to be as shown in FIG. 1, and one or more pairs of heating devices 5 and rolls 7 are installed in the vertical direction according to the desired width of the glass ribbon. And It is desirable that the positions of the heating device 5 and the roll 7 can be set freely in both the width direction and the height direction, and heating is performed before rolling with the roll. Heating is performed using a burner, a heater, etc. Also, as shown in FIG. 1, the heating device does not have to be installed so as to heat from the end of the glass ribbon toward the center, and is installed so as to face the glass ribbon. The glass ribbon surface may be heated.

  What is necessary is just to set the distance between rolls of the roll 7 suitably so that a desired glass ribbon width may be obtained. When the distance between the rolls of the roll 7 is less than 50% of the upper roll, the glass ribbon may not pass between the rolls or a new line may be generated. The upper limit is not particularly limited as long as it can be efficiently expanded in the width direction.

It is a side view of the example of an apparatus for carrying out the present invention. It is a front view of the example of an apparatus for carrying out the present invention.

1: Molten glass supply device 2: Molten glass 3: Uppermost roll 4: Liquid supply device 5: Heating device 6: Glass ribbon 7: Roll

Claims (3)

A method of forming molten glass flowing down from a molten glass supply apparatus into plate glass by passing between paired rolls, the roll comprising a base material made of a material or a structure capable of containing a liquid inside, While forming the glass ribbon through the liquid vapor film between the rolls while rotating the uppermost roll installed so that the roll is paired under the molten glass supply device, the molded glass ribbon is sent downward, A method for roll-out molding of molten glass, comprising: heating an end portion of the fed glass ribbon, and then rolling the glass ribbon with one or more rolls installed vertically below the uppermost roll. The distance between the rolls of a pair of rolls installed vertically below the uppermost roll to which the molten glass is supplied is 50% or more with respect to the distance between the rolls of the upper roll. A roll-out molding method for molten glass as described in 1. The method for roll-out molding of molten glass according to claim 1 or 2, wherein the liquid that forms the vapor film is water.